Carbohydrate Polymers 75 (2009) 58–62
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Degradation of different polystyrene/thermoplastic starch blends buried in soil
Daniela Schlemmer a, Maria J.A. Sales a,*, Inês S. Resck b
a Laboratório de Pesquisa em Polímeros (LabPol), Instituto de Química, Universidade de Brasília, Caixa postal 4478, Brasília-DF 70904-970, Brazil
b Laboratório de Ressonância Magnética Nuclear, Instituto de Química, Universidade de Brasília, Caixa postal 4478, Brasília-DF 70904-970, Brazil
a r t i c l e
i n f o
Received 22 April 2008
Received in revised form 6 June 2008
Accepted 13 June 2008
Available online 24 June 2008
0144-8617/$ - see front matter 2008 Elsevier Ltd. A
* Corresponding authors. Tel.: +55 61 3307 2179; f
E-mail address: email@example.com (M.J.A. Sales).
a b s t r a c t
Blends of PS and TPS were prepared using two different plasticizers: glycerol or buriti oil by solvent
casting technique. PS/TPS blends were submitted to degradation by soil burial tests in perforated
boxes for 6 months and later analyzed by TG and CPMAS 13C NMR. After degradation, blends with
glycerol presented less stages of thermal degradation and NMR signals of minor intensity compared
to the original blends. The presence of TPS at contents of 50% or greater improved the degradation
of the blends. After 6 months, PS/TPS blends with buriti oil presented only one thermal degradation
stage with a significant increase in mass loss. Moreover, all absorptions related to starch disappeared
in NMR spectra after soil buried test, probably due to the consumption of starch by microorganisms.
These results revealed that PS’s degradability can be improved when TPS plasticized with buriti oil is
added to it.
2008 Elsevier Ltd. All rights reserved.
A polymeric degradation is an irreversible process